Why Does My PC Fan Speed Up and Slow Down – [9 Fixes]

Does your PC fan exhibit erratic behavior, speeding up and slowing down unexpectedly? The fans inside your PC play a crucial role in maintaining the temperature of internal components such as the CPU and GPU. While it’s normal for fans to increase speed when temperatures rise, frequent fluctuations could indicate an underlying issue.

PC Fan Speed Up and Slow Down


  • Keep an eye on CPU and GPU temperatures to avoid fan fluctuations caused by overheating.
  • Dust can disrupt cooling; clean your PC and check thermal paste for optimal performance.
  • High CPU or disk usage can lead to increased fan speeds; use Task Manager to identify and address resource-heavy processes.
  • Ensure all fans work correctly within your PC for consistent cooling.
  • Regularly update BIOS and chipset drivers and check hardware compatibility for a stable computing experience.

Why Does My Pc Fan Speed Up and Slow Down?

Your PC fan speeds up and slows down to regulate the internal temperature of components like the CPU and GPU. High usage, dust accumulation, or hardware issues may contribute to these fluctuations. Regular maintenance and monitoring can help address and prevent such problems.

How to Fix CPU fan speeding up and slowing down?

Why Does My Pc Fan Speed Up and Slow Down?
CPU fan

To address CPU fan speed fluctuations, monitor and manage CPU temperatures, clean your PC regularly, check for malfunctioning fans, repair system files, update BIOS and chipset drivers, and ensure compatibility with the installed operating system. If issues persist, consult a professional for potential hardware faults or consider upgrading to a quality silent cooler for reduced noise.

Here, we’ll explore various methods to troubleshoot and fix this problem.

Method 1: Monitor CPU & GPU Temperature

One of the primary reasons for fluctuating fan speeds is elevated temperatures within your PC. Utilize free tools to monitor CPU and GPU temperatures, as overheating can trigger automatic increases in fan speed. Investigate further if temperatures are consistently high, identifying any applications or software causing the issue.

Method 2: Clean Your PC

Dust accumulation within the PC case acts as an insulator, hindering heat exchange and causing temperature spikes. Regularly clean your PC following proper guidelines, including checking and replacing thermal paste if necessary. This simple maintenance routine can significantly improve your system’s cooling efficiency.

Method 3: Monitor CPU and Disk Usage

Keep an eye on CPU and disk usage using the Task Manager. High CPU consumption can lead to increased temperatures, prompting faster fan speeds.

Identify and terminate resource-intensive processes to stabilize system performance. Ensure that terminating specific services won’t compromise system stability, addressing the root cause instead.

Method 4: Check if All Fans Are Working

Ensure that all fans inside your PC case are functioning correctly. Malfunctioning fans can disrupt the cooling system, leading to temperature irregularities. Address any non-functional fans promptly to maintain optimal airflow and cooling efficiency.

Method 5: Repair Your System Files

Corrupted system image files can contribute to various issues. Use System File Checker and DISM tools to repair these files, ensuring the overall health of your Windows computer.

Method 6: Update Your BIOS and Chipset Drivers

Fan speed irregularities may be linked to outdated BIOS versions. Check for manufacturer-specific software updates or download the latest version from the official website. Additionally, keep your chipset drivers up to date for improved system compatibility.

Method 7: Check Windows 11 Installation Hardware

Ensure your system meets the hardware requirements for Windows 11 compatibility. Running Windows 11 on unsupported hardware may lead to performance issues and potential damage. Consider switching to Windows 10 if your hardware is incompatible.

Method 8: Hardware Issue

Persistent fan speed fluctuations might indicate a hardware fault. Consult a professional PC repair technician to diagnose and address the root cause, especially if it involves a faulty power supply.

Method 9: Replace Your Cooler with a Quality Silent Cooler

If fan noise is the primary concern and your system is not experiencing performance issues, consider upgrading to a silent cooler. Quality silent PC fans can offer a quieter computing experience without compromising cooling efficiency.


Why does my PC fan randomly speed up and slow down?

The fan speed fluctuation is typically a response to changes in internal temperatures, primarily those of the CPU and GPU. When these components get too hot, the fans speed up to cool them down.

Is it normal for my PC fan speed to vary occasionally?

Yes, occasional variations in fan speed are normal as the system adjusts to changing temperatures. However, frequent or extreme fluctuations may indicate an issue that needs attention.

How can I monitor my CPU and GPU temperatures?

You can use free tools or the Windows Task Manager to monitor CPU and GPU temperatures. There are various guides available for monitoring CPU and GPU temperatures.

Why should I clean my PC regularly?

Dust accumulation inside the PC case acts as an insulator, blocking efficient heat exchange. Regular cleaning helps maintain optimal airflow, preventing overheating and erratic fan behavior.

What should I do if my PC fans are not working properly?

Check if all fans inside your PC case are working. Malfunctioning fans can disrupt the cooling system, leading to temperature irregularities. Repair or replace non-functional fans as needed.

Can high CPU usage affect fan speed?

Yes, high CPU usage can increase the CPU temperature, prompting the fans to run faster. Monitoring and managing CPU usage through the Task Manager can help stabilize fan speeds.

How do I update my BIOS and chipset drivers?

You can check for BIOS updates using your computer manufacturer’s dedicated software or download the latest version from the official website. Update chipset drivers for improved system compatibility.

Why would I consider replacing my cooler with a silent cooler?

If fan noise is bothersome and your system is not experiencing performance issues, replacing your cooler with a quality silent cooler can provide a quieter computing experience without compromising cooling efficiency.


Maintaining the health of your PC’s cooling system is crucial for optimal performance. By following these methods, you can identify and address the root causes of fan speed fluctuations, ensuring a stable and efficient computing experience.